Image transmission apparatus using information on rendered range

Abstract

An apparatus for transmitting image data through a network has an image rendering unit, an image processing device, a memory device, and an image transmitter. The image processing device is configured (a) to define a range surrounding an updated portion which has changed through displaying, of the displayed image sent from the image rendering unit, and to acquire position and range information of the defined range, (b) to compare the defined range with a range stored in the memory device, using the position and range information of the defined range and position and range information stored in the memory device, (c) to send the position and range information of the defined range to the memory device if there is no overlapping range between the compared ranges, and if there is an overlapping range between the compared ranges, to send position and range information of a new range surrounding the compared ranges to the memory device, and (d) when the image transmitter is ready for transmission through the network, to read image data of a latest image stored in the memory device, the image data corresponding to each item of the position and range information stored in the memory device at a time of transmission, to compress the image data in order to generate compressed image data, send the compressed image data to the memory device, and to initialize the position and range information stored in the memory device.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an image transmission apparatus and an image transmission system, and, more particularly, to an image transmission apparatus and system which are capable of reducing the amount of image data to be transmitted during periods of congestion on the network connecting the data source and display terminal.[0003]2. Description of the Related Art[0004]In recent years, applications in which images are sent to display terminals have continued to increase in the art. In such an application, an image generated by a personal computer, for example, is sent via a wired or wireless network to a remote image display apparatus or terminal such as a projector or the like to be displayed thereby. Data generated by the personal computer are sent in the data format of a presentation software program to the remote image display terminal, which converts the data into image data and displays an image based on th...

AI Technical Summary

Benefits of technology

This approach reduces transmission delay and maintains image quality by controlling the amount of data transmitted based on current network bandwidth, minimizing the need for continuous high compression and reducing CPU load.

Problems solved by technology

Moreover, there may not even be a local display terminal in an application configuration such as when a network server serves as the source of image data to be transmitted to the remote image display terminal.

However, the additional component makes it difficult to meet requirements for smaller and less expensive image display terminals.

However, it takes several seconds to transmit the image data through an ordinary network to the remote image display terminal, because the amount of image data is generally quite large.

However, with the systems disclosed above, it was difficult to control the amount of transmitted image data such that transmission delay was reduced between an image transmission apparatus and an image reception apparatus, depending on the transmission capability of a network.

To control the amount of image data to be transmitted to reduce transmission delay, it was necessary to compress the image data at a high compression ratio in order to reduce the amount of image data to be transmitted, which lowers the quality of the displayed image.

However, if the image data were to be continuously compressed at a compression ratio to reduce transmission delay, the network bandwidth was not effectively used, and the quality of displayed images was degraded.

Even if the amount of image data to be transmitted was reduced by a general image compression process, when image data were sent in an amount exceeding the transmission capability of the network, the transmission delay of received image data increased.

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